Abrading operations such as micro-finishing are often a vital step when manufacturing products. Abrading operations refer to the application of an abrasive to a workpiece. Abrading operations are typically performed to create a finer finish and/or to remove defects from a workpiece. As used herein, the term “workpiece” means a substrate whose surface is to be modified. Abrasive articles have long been used to grind, dimension, clean, polish, or otherwise refine the surface of substrates (workpieces). Suitable workpieces include but are not limited to those of metal, wood, plastic, composite, ceramic, and/or combinations. For example, many components of engines must be abraded to ensure proper operation and eliminate engine failures that would otherwise be caused. Camshafts, crankshafts, and transmission shafts are examples of such engine components. These engines are employed in automobiles, trucks, agricultural equipment, ships, boats, etc.
These abrading operations are performed by an abrading machine that utilizes an abrading article as an abrasive. The abrading article may be of various forms depending upon the particular purpose of the abrading operations. Abrasive articles generally fall into but are not limited to three categories: bonded abrasives, nonwoven abrasives, and coated abrasives. All of these categories contain abrasive particles secured in a binder. The term “abrasive particle” means a particle having sufficient hardness to alter the surface of a workpiece. The term “abrading” means the activity or process by which a workpiece is modified by inducing relative motion between an abrasive article and the workpiece. The term “coated abrasive backing” means the sheet-like member onto which abrasive particles are adhered by a binder. Examples of an abrading article include film, paper, or cloth having an abrasive coating on at least one side and abrading articles also include structured abrasives such as the Trizact abrasive from 3M of St. Paul, Minn. The classification of the abrasive coating is indicated by a grade assigned to the abrading article such that the abrading article is selected for a particular abrading operation by reference to its grade. As used herein, abrading article includes all grades or abrasiveness.
In regards to engine components finishing, typically the abrading article extends from a reel or winder at a source area of the abrading machine, through an abrading zone where a workpiece that is to be abraded is positioned, and then onward to a collection area. The abrading article is applied by the machine to the workpiece within the abrading zone as the workpiece rotates or otherwise moves in relation to the article. The abrading article is advanced by the machine as portions of the abrading article become worn. Eventually, the amount of abrading article on the reel or winder at the source area is depleted and a new reel or winder of article must be installed such as by splicing the new article to the end of the previous article.
Installing the article on this type of abrading machine is a largely manual task that is vulnerable to human error. One example of an error is installing the article with the abrasive side facing the wrong direction so that the abrasive is never brought into contact with the workpiece. This can occur because it can be difficult to distinguish the abrasive side from the non-abrasive side. When this occurs, any workpiece that is abraded with the article is not abraded properly and may be faulty as a result. Furthermore, if the error is not detected, many workpieces may be improperly abraded until the article is depleted and another reel is installed. Furthermore, the next several reels may be installed backwards as well if the installer does not realize a mistake has been made.
When the new article is spliced onto the end of the existing article, the connection of the two ends is often done using splicing tape. Splicing tape creates the potential for improper abrading due to the area of the article where the splicing tape is present being applied to the workpiece. Thus, an operator must ensure that the splicing tape is advanced beyond the abrading zone prior to the article being applied to the workpiece, and this presents another instance where human error may lead to faulty workpieces.
Another issue that occurs on occasion results from the abrasive article breaking when being applied to a workpiece. When this occurs, any subsequent attempts to abrade workpieces will fail because the article is no longer properly held in place on the workpiece by the machine. An operator must intervene by halting the abrading machine and re-feeding the article through the machine prior to the abrading operations continuing. Conventional systems attempt to detect a broken article by utilizing a mechanical flag in contact with the article that moves when the article moves and that breaks a beam of light once moved to register whether the article has moved. However, this flag system is prone to errors due to residue causing the flag to resist movement and due to the flag occasionally requiring an increment of movement to break the beam that is larger than the appropriate increment of article movement. Accordingly, the operator must continue to monitor the machines to determine whether the article has broken, and this also presents an instance where human error may lead to faulty workpieces and/or inefficiencies.
Abrading often involves multiple stages, where the workpiece is moved from one abrading machine to the next with each abrading machine applying a finer grade abrading article to the workpiece. Abrading machines in close proximity often utilize different grades of article, and the operator who installs the article must install the correct grade on a particular machine to maintain the proper sequence of abrading. This situation gives rise to yet another opportunity for human error to result in faulty workpieces due to the operator installing the improper grade of article.
What is desired in the industry is an increased user friendly system for finishing workpieces, including engine components.